Quantitative imaging tools such as computer tomography (CT) and magnetic resonance imaging (MRI) are used to image various tissues such as the brain heart, and joints. For example, in the brain, various disorders such as stroke, autism, Alzheimer Disease, Multiple Sclerosis, and schizophrenia, can be imaged using these and other known techniques. Such images often display the regions that are at risk or are damaged, e.g., with a structural or functional lesion, caused by the disease or disorder, or by physical or neurological trauma. Many of these other diseases, such as stroke, have clinical rating scales that are numerical and correlate physical behavior and degree of recovery with physical or functional tissue trauma, such as in the brain.
For example, in an attempt to better classify stroke patients (and study stroke patients as groups), a number of standardized clinical rating scales have been developed, such as the NIH Stroke Scale (NIHSS) score. The NIHSS is a 15-item, clinical evaluation instrument used in clinical trials and practice to assess neurological outcome and degree of recovery.
Such assessment tools assign a numerical score (e.g., 0 to 42 in the case of the NIHSS) to attempt to summarize a given patient's degree of disability based on a qualitative evaluation of the patient. In general, the higher the score, the higher the deficit. Such scores are widely used as indicators of outcome for stroke.